Boundary Mics & Auto Mic Mixers
Sep 13, 2013 3:18 PM,
By Mike McIntyre, CTS-D, EST-L2+
In this showcase, we will explore interesting solutions to common problems facing AV integrators and live audio professionals. With the miniaturization of electronic components, some extremely smart and small devices are available for us to use. Some of the best boundary-type microphones are included in this section along with the most intelligent class of automatic mic mixers.
AKG’s MB series of mini-boundary, super-cardioid microphones feature an aesthetically pleasing low profile when installed. The MB4, designed for multiple microphone applications—such as teleconferencing, distance learning, boardrooms, courtrooms, and TV or theatrical application—has an attached 15ft. cable leading to an XLR-type output connector with built-in electronics and can be mounted under shelves, on walls, etc., using double-sided sticky tape, which is provided. It is powered by 12V-48V phantom power, and is low-impedance balanced.
Audio-Technica PRO44
Audio-Technica’s PRO 44 is a wide-range condenser microphone with a hemi-cardioid (half-space cardioid) polar pattern. It can be powered from any external 9V to 52V DC phantom power source and comes with a 25ft. cable with TA3F and XLRM-type connectors for use between the microphone and electronics input. With the Audio-Technica’s fixed-charge “back plate” construction, a gold-vaporized diaphragm just two microns thick can be used, which reduces moving mass substantially, improving frequency response and transient response while reducing distortion. The microphone element is enclosed in a rugged housing with a black finish. The rubber non-slip bottom pad minimizes mechanical coupling of surface vibrations to the microphone. The high sensitivity of the PRO 44 ensures useful output to most mixer, tape recorder, and amplifier inputs. It will provide undistorted output even in sound fields as loud as 114dB SPL.
beyerdynamic Classis BM 32
beyerdynamic’s Classis BM 32/33/34 condenser boundary microphones—ideal for tele/videoconferencing applications, and the recording and amplification of roundtable discussions—are designed for flush mounting into tabletops or ceilings. Featuring Scudio technology, the mics are insensitive to wireless communication devices, such as mobile phones. The Classis BM 32 has a half-cardioid polar pattern, which increases the gain-before-feedback and decreases the amount of diffuse ambience. The Classis BM 34 corresponds to the Classis BM 32, but is provided with a bass roll-off filter. The Classis BM 33 has a half-spherical polar pattern making it ideal for large rooms. The high sensitivity guarantees a constant output level even from long distance sources. Elastic bearing rings achieve mechanical isolation from the mounting surface, and therefore offer effective sound isolation of the microphone.
The 930VPL by CAD Audio is a continuously variable polar-pattern condenser boundary microphone with a programmable membrane switch, LED, and logic interface. Designed to resist interferences from cell phones and two-way communication devices, the 930VPL features a dual output-connector design that allows the cable to exit the rear or underside of the mic. When mounted on a flat surface, it will take advantage of the “boundary effect” signal-to-noise ratio increase. This microphone comes with 30ft. of detachable microphone cable that is terminated with a standard 3-pin XLRM-type connector, and features logic I/O functions that can be used with automatic mixers, teleconferencing systems, and control systems. The logic input can remotely control the LED, as well as the membrane-switch activation. The exact mode of operation can be set with the dipswitch on the underside of the microphone, while the continuously variable polar pattern can be precisely tailored for the best performance depending upon the application or environment.
Clockaudio ARM 102-RF
The ARM 102-RF by Clockaudio features a low-profile boundary layer through-table design with a cardioid polar pattern. Able to automatically extend, retract, and lock the Capsule Module away to leave only 3mm protruding on top of the table, the ARM 102-RF has a built-in motor that is operated by a control box ARM – C and features a robust brass construction that includes 6.6ft. of audio cable and 6.6ft. of control cable. An integral phantom power module is provided requiring 9VDC to 48VDC.
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Boundary Mics & Auto Mic Mixers
Sep 13, 2013 3:18 PM,
By Mike McIntyre, CTS-D, EST-L2+
Dan Dugan Sound Designs’ Model E-1A automatic mixing controller helps audio mixers handle multiple live mics without having to adjust their individual faders. Designed for news panels, sports commentary, conference reinforcement, multiple wireless mics for theater, boardrooms, civic meeting, and distance learning, this 8-channel (analog) or 16-channel (digital) signal processor patches into the input insert points of an audio mixing console. Detecting which mics are being used and making fast crossfades, it frees the mixer to focus on overall balance instead of adjusting many faders. The Model E-1A’s voice-controlled crossfades track unscripted dialogue perfectly, eliminating cueing mistakes and late fade-ups while avoiding the choppy and distracting effects common to noise gates.
The SPN812 is an eight-input, 12-output 1RU mixer in Lectrosonics’ Aspen series of audio processing products. Ideal for applications ranging from small installations to more sophisticated multilayered systems, the SPN812 features ultra-low noise input preamps, a full crosspoint matrix with 48 inputs, and unlimited input expansion. It is also TCP/IP Ethernet addressable and allows seamless automixing at the matrix crosspoints using PGA. Simultaneous multi-point third-party and native control is also featured, along with automatic master/slave detection, while a single Cat-6 interconnection carries data, audio, and control signals.
Peavey S-4
Peavey’s S-4 can be used as a plug-in or standalone mixer, and up to 10 S-4 units can be linked together via TRS cables to provide up to 40 gain-shared inputs. Automix not only simplifies the mixing of spoken-word microphones, but also improves sound quality and increases available microphone gain for soft-spoken individuals. Once engaged, it monitors the levels of these channels and automatically turns down unused or low priority inputs to give priority to the main microphone, minimizing ambient noise and feedback. The S-4’s direct outputs are processed, enabling it to be used in-line with a standard mixing console to add automatic mic mixing. Another feature is Mid Morph equalization, which is actually two EQ controls in one. When the knob is cut, it pulls out low-mid frequencies; when boosted, it shifts to an upper-mid frequency that brightens the vocal range. Each channel is full featured with compression, equalization, and PFL.
Rane AM2
Rane’s AM2 is both an 8-channel, gain-sharing automatic mic mixer and a Rane RAD. Use it as a standalone mic-only mixer, add more gain-shared mics using up to seven additional AM2 automixers, and/or use the RAD port to transport the mic mix via a Rane Mongoose to a CobraNet network. Each of the eight XLR mic inputs offers front-panel input level controls feeding a gain-sharing automatic mixer. Rear-panel, three-position selectors support dynamic mics (no phantom power), condenser mics (48V), or line input optimized for wireless receiver outputs (+10dBu max). All level controls come with front-panel signal and overload indicators. The AM2 is optimized for automixing speech. The mic inputs have a fixed 100Hz to 7kHz bandpass filter to provide the best voice-only automatic mixing using the gain-sharing algorithm.
Revolabs Executive Elite
Revolabs’ Executive Elite 4- and 8-channel wireless microphone systems are designed for boardroom and conference room audio solutions. Using a distributed architecture that separates audio equipment from radio equipment, Executive Elite remote antenna receivers and base DSP units are connected via Cat-6 cable supporting Power over Ethernet (PoE), enabling distributed or in-room installations. Featuring cloud-based management and future proofing thanks to DECT protocol that protects against frequency changes, the Elite systems also use AES 256 encryption with automatic key updates every 60 seconds for secure operation. The Executive Elite receiver pairs with the entire suite of microphones and adapters, including omni-directional, directional, gooseneck (6in. and 12in. variations), and wearable microphones, as well as XLR and TA4 (mini XLR) adapters.
Samson CM11B
The CM11B by Samson is a low-profile, surface-mount boundary microphone good for flat surfaces, such as conference room tables, altars, or hanging on walls. It features a permanently charged condenser element with an omnidirectional pickup pattern, which provides linear pick-up in a 360-degree pattern. Although the CM11B is small in size, all of the electronics are contained within the body, eliminating the need for any external electronics pack. It is fitted with a standard 3-pin miniature male XLR connector, includes a 30ft. mini XLR to standard XLR cable, and operates on standard 9V to 52V phantom power. The CM11B is built using heavy-duty, die-cast construction with reinforced steel grille screen, and a heavy neoprene rubber pad is added to the bottom of the unit to decouple the microphone from the surface, helping to reduce unwanted pick-up noise.
Sennheiser e 912
Sennheiser’s e 912 is a pre-polarized condenser boundary microphone with half-cardioid pick-up pattern. Its acoustic properties have been optimized for instruments, vocals, and speech. The e 912 is good for pianos, theater, opera productions, conference applications, altars, and lecterns. To optimally match the installation environment, the e 912 is available in black or crème white.
Shure MX396
Ideal for conference room installations, Shure’s Microflex Multi-Element boundary microphone comes in two- or three-element configurations: The MX396 dual-element is a 0-180-degree mic and the MX396/TRI is a dual-element, 90-0-90 mic, adjustable to 120-120-120 degrees. This solution combines the coverage of multiple microphones into a small, compact package. Each unit features individual audio output for each element, a bi-color status indicator, programmable mute switch, logic input/output for remote LED and mute control, and Shure’s proprietary CommShield technology to ensure resistance to intense nearby radio signals.
The D-901 from TOA features a modular design that supports up to 12 mic/line inputs and eight line outputs with flexible RS-232 or contact-closure remote control. Audio processing tools include automixing, feedback suppression, multi-band parametric filters, compressors, limiters, noise gates, crossovers, and delays. Full input-to-output matrixing allows users to store and recall any input-to-output combination for multi-zone or room-combining applications. The unit can be programmed via the front-panel display or with configured off-site with PC control software for later uploading.
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